Certain investigations on soft switching and intelligent controllers based inverters for enhanced performance

Abstract

Nowadays, the power electronics systems are required to develop less expensive, smaller and reliable system. Inverters are more and more used in many industrial applications such as AC power supplies, uninterruptible power systems, motor drives, induction heating, and etc., as the demand for high efficiency, high switching losses and cost effective inverter filter size to increase, inverter design has become more challenging and complex than ever before. As most of the losses are frequency dependent, soft switching techniques are developed to reduce switching losses. In this thesis focused to use only one auxiliary circuit and design controllers for switching inverters to achieve zero voltage switching. In order to investigate and design a suitable controller for soft switching inverter for improving performance and reduced voltage stress are interesting aspects of present day research. In the soft-switching inverter, zero-voltage switching is achieved by proper selection of main and auxiliary switches conduction period. Artificial controller is used to find out the exact switching period of main and auxiliary switches. The present work concentrates on the pioneering fuzzy logic and neural network based soft switching inverter for industrial application. The Induction motor when provided by artificial controller is thus able to give better performance under steady state conditions. Since, the conduction period of main and auxiliary switches is not always the best one, a fuzzy logic and neural network controller approach is used to find out the exact switching period. Further, fuzzy logic and neural network based soft switching three phase inverter with reduced component count has been proposed. Hence, for efficient operation of soft-switching inverter, it is necessary that all switches work in zero-voltage switching conditions. The proposed intelligent system provides the exact switching period to attain zero-voltage switching of the main and auxiliary switches. Extensive analysis and discussion on simulation res